Rebuilding King Crab
Length with intro/outro: 4:46
Download mp3 file: Rebuilding King Crabs [4.4 MB]
In the back of what amounts to a warehouse on Seward's waterfront, the rebirth of the Alaska's once-famous Kodiak Island red king crab fishery is taking shape. That's this week's CoastWise Alaska.
Just a few decades ago, red king crab hauled from the icy-cold waters around Kodiak Island truly was king when it came to making a lot of fast money in Alaska's commercial fisheries. Fishermen braved fierce seas and earned thousands of dollars from boat-busting catches of the giant crustacean. But the boom wasn't to last. Within a few years, the red king crab were gone and fishermen had moved on.
Fast forward to today. Kodiak red king crab stocks still haven't recovered. Scientists say that while mismanagement and overfishing may have caused the collapse, ocean conditions are keeping the stocks from rebuilding.
Meanwhile, in the Bering Sea near the remote Pribilof Islands, another species, and color, of king crab—blue king crab—has rapidly declined in recent years.
To help bring both species back to their former glory, scientists, coastal communities, and fishermen have formed a unique collaboration aimed at giving nature a helping hand. The Alaska King Crab Research, Rehabilitation and Biology program seeks to learn how to hatch and raise wild king crab inside a hatchery, in the hopes of one day releasing them into the wild.
Ben Daly is a research biologist with the program.
Daly: "That's the ultimate goal, to be able to release juvenile king crab back into the ocean so that they could maybe contribute to the natural stocks."
Much research is needed before that decision can be made. Daly says high on the list of priorities is conducting genetic studies that will ensure that any release of hatchery-born crab doesn't jeopardize the genetic heath and variability of the wild stocks.
Daly: "They're also looking at genetics of red king crab stocks, trying to understand different genetic stocks within the state of Alaska. Is one region independent from another genetically, or are they all kind of blended together? And so that kind of stuff needs to be addressed so that any release would not compromise the genetic variability of the natural stocks, because that's one thing of course we don't want to do."
A look inside the program's facilities at the Alutiiq Pride Shellfish Hatchery in Seward reveals large tanks connected by a maze of pipes that bring seawater in from the fjord just yards away. The clatter of pumps and rushing water echo inside the warehouse-like building. In some tanks are adult female crab—giant red king crab from Bristol Bay and blue king crab from Norton Sound. In other tanks are their offspring—millions of king crab larvae—each no bigger than a pencil eraser.
Daly says research at the hatchery itself is focused on developing the science and tools needed to hatch and raise millions of king crab larvae to the juvenile stage. A major part of that work is centered around raising tiny brine shrimp, called artemia, that are fed to the ever-hungry larvae.
Daly: "We hatch artemia, which are brine shrimp, hatched from eggs. So, every day we hatch these artemia and put a certain amount of artemia in the tanks and change out these filters so the food is trapped in the tank during the day and we change the filters at night so the food gets flushed out overnight, so by the next morning all the old artemia is flushed out and we can put fresh artemia in the morning."
Elsewhere in the state, scientists are working to understand a host of complicated problems. In Kodiak, federal researchers are studying the effects of different diets and light on larval development. In Juneau, University of Alaska Fairbanks scientists are working to better understand the growth and habitat requirements of juvenile crab in the wild. Scientists there also are trying to develop tiny tags to monitor hatchery-born crab that might one day be released into the wild.
Daly: "We've sent them juvenile red king crab and blue king crab from the hatchery here in Seward down to Juneau where they are doing different growth studies with the juveniles; different tagging studies trying to develop physical tags for the juvenile crabs so they could be potentiallly identified from wild crab. They are also looking at habitat issues, trying to tease apart what is the best habitat in the wild for these young juvenile king crab."
Daly says much needs to be learned about raising king crab inside a hatchery, and much needs to be known about how hatchery crab would fare once released into the wild. Getting those answers will help fishery managers and state policymakers decide when the time is right to begin enhancing the wild stocks.
CoastWise Alaska is a production of the Alaska Sea Grant College Program, University of Alaska Fairbanks, which offers outreach and technical assistance to help Alaskans wisely use, conserve, and enjoy the state's marine and coastal resources. Check out our Web site at CoastWiseAlaska.org.